Mafuyu came from a wealthy family, and as such, grew up highly sociable. As a young girl, Mafuyu and her mother were victims of a hit-and-run incident. Her mother shielded her from impact, but ended up in critical condition and comatose. Confused, Mafuyu was left to observe the aftermath of the incident, which ended in the culprit's trial. The prosecutor on the case, Vertx would investigate every detail and bring the perpetrator to justice, causing Mafuyu to fall in love with the man. At some point after the culprit's trial, Mafuyu's mother ended up succumbing to her injuries.

Mafuyu met Saori Shirosaki in her early teens, and the two grew close to each other. They grew distant overtime, but reconnected in law school and became best friends. One day, Mafuyu found out Morita had just married another woman. Later that day, Saori introduced Mafuyu to Takayuki Yagami at Bar Tender, and they became friends. Although Mafuyu and Yagami shared mutual romantic feelings for each other, they never dated due to Yagami's grief following Shinpei Okubo's conviction. While the two never ended up rekindling their relationship, Mafuyu still kept tabs on Yagami and the two appear to be on amicable terms.

Scene: Bar Tender, where Mafuyu, Saori, and Yagami are catching up.

Mafuyu: "It's been a while since we've all been together. How have you been, Yagami?"

Yagami: "Busy as ever. Cases never stop. How about you, Saori?"

Saori: "Hectic, but managing. It's great to unwind with friends."

Mafuyu: "Do you miss our law school days, Saori?"

Saori: "Sometimes. But we've grown so much since then. We're still here for each other."

Yagami: "Life has its twists and turns, but they shape us."

Mafuyu: "Yagami, I admire your dedication. Even with Okubo's case, you stayed true."

Yagami: "Thanks, Mafuyu. And I know things have been tough for you, especially with Morita."

Saori: (holding Mafuyu's hand) "We've all had heartbreaks, but we keep moving forward."

Mafuyu: "Exactly. We can’t let the past hold us back."